Nothing short of PvE vs PvP gets everyone riled up like the flight model!
Here's some succinct answers to help put / remove my many "umms" and "ahhs" from the Forum Feedback section of Wing Man's Hangar.
1) The physics simulation is Newtonian
2) There is no drag.
3) The IFCS (Intelligent Flight Control system) generally handles taking the pilot's inputs (desired pitch, yaw, roll and speed) and translates them into actions for the thrusters and ship to take to adjust the ship's velocity vector in the direction the pilot wishes to go. This system will do it within human acceptable tolerances (it will not change your velocity vector in such a way as it could cause harm to the pilot)
4) Slowing down is caused by the pilot telling his IFCS that he wants to be traveling at a lower speed. The IFCS then communicates with the ships thrusters to adjust the ship's velocity accordingly.
5) If you turn you engines and IFCS off you will continue to coast at the same velocity.
6) Fuel is consumed by using your thrusters or main engines. If you coast you will not be using fuel, but making velocity vector changes will consume fuel.
7) More advanced IFCS systems will allow you to turn of parts of its overrides or allow it to interpret you inputs differently - for instance you could tell it you want to go into an "orientation" not "vectoring" mode where it will take your joystick inputs as solely ship orientation inputs and not try to correct your ship's velocity vector to be aligned in the direction your ship is pointing (the famous Battlestar Galactica maneuver).
8) We will limit the top speed of ships you can fly for technical issues (physics engines have problems when the numbers get too big) and fun - figuring out an intercept course for an opponent traveling at 0.2 speed of light (which is our fictional max for practical spaceflight in 2943) maybe be challenging if you're a mathematician or physicist but not what I call fun gameplay.
9) This top speed will be less than the top speed of weapons.
10) Top speed will probably be dependent on ship class but we haven't balanced this so it may be a matter of all ships having the same cap but the smaller faster ones can reach that limit much quicker (and therefore put some distance between them and their pursuers even if they go to max). This needs to be tuned so that people with the right kind of ships can run from a fight. The idea is that once you get enough separation between you and a hostile you can make the jump to autopilot / warp speed (using the Star Trek term), which is how you cover big distances in-system (essentially at that 0.2 lightspeed (c) number I mentioned). Just at these speeds you're not maneuvering - you're just accelerating and decelerating in a straight line. Think of it as human (player) controlled flight for the lower combat / docking speeds and then when wanting to warp to a destination (say a planet or a jump point) you hand control over to your ship's flight computer which handles plotting the trajectory and accelerating you to the 0.2 c speed that a RSI quantum drive can achieve.
11) I do know what G-Force is I use the term as a measure of acceleration on the human body as its good short hand for people to grasp the concept of forces acting on a body when accelerating and decelerating. You may be interested to know that "..The accelerations that are not produced by gravity are termed proper accelerations, and it is only these that are measured in g-force units. They cause stresses and strains on objects. Because of these strains, large g-forces may be destructive..." Occasionally people think it is only to do with gravity and earth bound flight but that's actually incorrect - its just that's the case we're most familiar with. And yes these forces come into play when accelerating and decelerating in space and until we develop some system to increase our tolerances to the effects of this acceleration they will be the limiting factor on how aggressively we could change the velocity vector of a ship, irregardless of whether we are in the atmosphere or not. Its also interesting to note that we're built to withstand much greater accelerations in certain directions - modern day pilots can withstand 9 G but much less negative Gs. Its why you see pilots rolling and pulling back on the stick when attempting aggressive maneuvers rather than pushing forward or yawing with a rudder. The same will be true in space. We're going to factor in G-Force in the simulation, and allow pilots to push the boundaries (or switch the IFCS safety off) in search for a little advantage, but beware if you back (or red) out in a dogfight you may come to floating in space next to the smoking wreck of your ship!
-Chris